Logic Programming

Hardware and software systems are growing everyday in scale and functionality. This increase in complexity increases the number of subtle errors. Moreover, some of these errors may cause catastrophic loss of money, time, or even in many cases human life. A major goal of ...

Abstract. Motivation plays a key role in the learning process. This paper describes an experience in the context of undergraduate teaching of Artificial Intelligence at the Computer Science Department of the Faculty of Sciences in the University of Porto. A sophisticated competition framework, which involved Prolog programmed contenders and game servers, including an appealing GUI, was developed to motivate students on the deepening of the topics covered in class. We report on the impact that such a competitive setup caused on ...

The hyper-automaton is introduced as a model of complex control algorithms. The model reflects basic aspects of control algorithms: presence of an external environment, cyclic and event-driven functioning, synchronism, hierarchical structure and logical parallelism. The paper introduces basic definitions and conceptual means of hyper-automaton model, which encourage program implementation of the algorithms. A new kind of functional polymorphism we name event- driven polymorphism is distinguished and discussed.

White Paper C discusses: (a) key recommendations to the decision-makers; (b) understanding the risks; (c) scenario planning at the policy level; (d) future scenarios and recommendations; (e) conclusion. This white paper examines the A.C.T. Sustainable Energy Policy.

A detailed generic model of the control design process is introduced and discussed. It is used for surveying different formal approaches in the context of PLC programming. The survey focuses on formal methods for verification and validation (V&V). The varying works in this area are categorized using three criteria: the general approach (A) to the task (model based, constraint based or without a model), the formalism (F) (Petri net, automata, etc.,) used to state the formal description, and the method (M) (model-checking, reachability analysis, etc.,) used to analyze the properties. Based on these three criteria (A-F-M) a three letter code for V&V approaches is introduced. Some works from the multitude of V&V research are presented and categorized using this new system

The spreadsheet application is among the most widely used computing tools in the modern society. It provides great usability and usefulness, and it easily enables a non-programmer to perform programming-like tasks in a visual tabular " pen and paper " approach. However, due to its mono-directional dataflow, spreadsheets are mostly limited to bookkeeping-like applications. This paper shows how the spreadsheet computing paradigm is extended to break through this limitation for solving constraint satisfaction problems. We present an enhanced spreadsheet system where finite-domain constraint solving is well supported in a visual environment. A spreadsheet-specific constraint language is constructed for general users to specify constraints among data cells in a declarative and scalable way. The new spreadsheet system significantly simplifies the development of many constraint-based applications using a visual tabular interface. Examples are given to illustrate the usability and usefulness of the extended spreadsheet paradigm.

Thanks to more powerful hardware and a new generation of learning algorithms, artificial intelligence is supporting the automation of a number of tasks and activities that are changing the job landscape as much as they have impacted on our everyday life. The first part of the chapter introduces artificial intelligence from its origins: its definition and its main research and application areas. The nature and the importance of machine learning for artificial intelligence applications are presented in the second part of the chapter. Existing approaches to machine learning are also classified and illustrated. The third part describes artificial intelligence tools and solutions by supported functionalities and automated tasks. Cases of applications in tourism are provided, from the best known and widely adopted, e.g., personal assistants, to the most challenging, i.e., semantic systems. Future trends and risks related to the applications of artificial intelligence are considered in the last part of the chapter.

Искусственная нотации BFT предназначена для улучшения коммуникации между носителями различных формальных систем. Нотация дополняет текст логическими конструкциями удобными для осмысленного чтения и одновременно пригодными для машинного анализа. В отличие от иерархической разметки знаний формата XML или JSON-LD, предложенный формат BFT имеет сетевую модель.

For many years, the non-monotonic reasoning community has focussed on highly expressive logics. Such logics have turned out to be computationally expensive, and have given little support to the practical use of non-monotonicreasoning. In this work we discuss defeasible logic, a less-expressive but more efficient non-monotonic logic. We report on two new implemented systems for defeasible logic: a query answering system employing a backward-chaining approach, and a forward-chaining implementation that computes all conclusions. Our experimental evaluation demonstrates that the systems can deal with large theories (up to hundreds of thousands of rules). We show that defeasible logic has linear complexity, which contrasts markedly with most other non-monotonic logics and helps to explain the impressive experimental results. We believe that defeasible logic, with its efficiency and simplicity, is a good candidate to be used as a modelling language for practical applications, including modelling of regulations and business rules.

Every writer knows putting words on paper is a difficult task.
Sometimes the difficulties become insurmountable. He got
himself into a state of frustration in writing when the flow of ideas
stopped. A writer got stuck and banged his head against the wall
for long hours instead of writing. His struggle becomes futile
without getting the desired result. Despite being armed with
knowledge and language ability, he cannot execute his task. The
objective is primarily to understand the cognitive processes in
writing employing different approaches: mechanistic writing and
developmental organic writing models. This understanding is
derived and inferred from some learning theories such as the
behaviourist and mechanical models coupled with issues related
to the functions of brains and ‘mind’ in writing as expounded by
some known linguists and writers. It is hoped that by
understanding the cognitive processes at work in writing, anyone
who intends to write can benefit in terms of enhancing his writing
skill and making writing a challenging and enjoyable task. The
study is on a qualitative analysis of abook written by Peter Elbow
on `Writing Without Teachers` and `Writing with Power`.
Compared to the researchers, the data collected from his
experiences will embark on the meaning of `organic writing`.

Dialogue games are a dynamic form of argumentation, with multiple parties pooling their arguments with the intention of settling an issue. Such games can have a variety of structures, and may be collaborative or competitive, depending on the motivations of the parties. Strategic argumentation is a class of competitive dialogue games in which two players take turns in contributing their arguments, each attempting to have an issue settled in the way that they would prefer. Thus strategic argumentation games are less about discovering a joint truth than about a player imposing their view on an opponent. They are reflective of legal argumentation. In the games we study, players have perfect information of the moves players make, but incomplete information on the possible moves (arguments) that other players have available to them. We look both at games using logically structured arguments and games using abstract arguments. We show that playing these games can be computationally hard. We also examine issues of corruption in such games, and discuss approaches to foiling it.

A personal archive of material related to formal methods has been deposited at Swansea University by the author in 2018. This paper documents the contents of the archive and includes associated publications. The archival material forms part of a larger History of Computing Collection founded by Prof. John Tucker at Swansea in 2007 and held at the University. It is hoped that this paper can aid future archivists with placing the material in context.

Three classic distinctions specify that truths can be necessary versus contingent, analytic versus synthetic, and a priori versus a posteriori. The philosopher reading this article knows very well both how useful and ordinary such distinctions are in our conceptual work and that they have been subject to many and detailed debates, especially the last two. In the following pages, I do not wish to discuss how far they may be tenable. I shall assume that, if they are reasonable and non problematic in some ordinary cases, then they can be used in order to understand what kind of knowledge the maker's knowledge is. By this I mean the sort of knowledge that Alice enjoys when she holds the information (true content) that Bob's coffee is sweetened because she just put two spoons of sugar in it herself. The maker's knowledge tradition is quite important but it is not mainstream in modern and analytic epistemology and lacks grounding in terms of exactly what sort of knowledge one is talking about. My suggestion is that this grounding can be provided by a minimalist approach, based on an information-theoretical analysis. In the article, I argue that (a) we need to decouple a fourth distinction, namely informative versus uninformative, from the previous three and, in particular, from its implicit association with analytic versus synthetic and a priori versus a posteriori; (b) such a decoupling facilitates, and is facilitated by, moving from a monoagent to a multiagent approach: the distinctions qualify a proposition, a message, or some information not just in themselves but relationally, with respect to an informational agent; (c) the decoupling and the multiagent approach enable a re-mapping of currently available positions in epistemology (Classic, Innatist, Kant's and Kripke's) on these four dichotomies; (d) within such a re-mapping, two positions, capturing the nature of a witness' knowledge and of a maker's knowledge, can best be described as contingent, synthetic, a posteriori, and uninformative and as
contingent, synthetic, weakly a priori (ab anteriori), and uninformative respectively. In the conclusion, I indicate why the analysis of the maker’s knowledge has important consequences in all those cases in which the poietic (constructive) intervention on a system determines the truth of the model of that system.

"The Dictionary of Computing gives the following (abridged) definitions for a compiler and decompiler (or reverse compiler):

compiler A program that translates high-level language into absolute code . . .

decompiler A program that attempts to . . . translate back from machine code to something resembling the source language. The task is difficult and not often attempted.

The following sections are intended to show how a decompiler may be constructed given only a knowledge of or access to the specification for a forward compiler, and some facility with Prolog or other high-level languages. It is easy to do and
should be attempted more often.

Decompilation is only useful, of course, if the object code is available and it is
required to reproduce the higher level `original' as an intermediate stage to aid understanding
or restructuring. The decompiled code can then be abstracted to a specification
by other techniques developed by the REDO project,"

This work concerns the problem of modelling evolving prospective agent systems. Inasmuch a prospective agent [1] looks ahead a number of steps into the future, it is confronted with the problem of having several different possible courses of evolution, and therefore needs to be able to prefer amongst them to decide the best to follow as seen from its present state. First it needs a priori preferences for the generation of likely courses of evolution. Subsequently, this being one main contribution of this paper, based on the historical information as well as on a mixture of quantitative and qualitative a posteriori evaluation of its possible evolutions, we equip our agent with so-called evolution-level preferences mechanism, involving three distinct types of commitment. In addition, one other main contribution, to enable such a prospective agent to evolve, we provide a way for modelling its evolving knowledge base, including environment and course of evolution triggering of all active goals (desires), context-sensitive preferences and integrity constraints. We exhibit several examples to illustrate the proposed concepts.

Defeasible Logic Programming (DeLP) is a suitable tool for knowledge representation and reasoning. Its operational semantics is based on a dialectical analysis where arguments for and against a literal interact in order to determine whether this literal is believed by a reasoning agent. The semantics GS is a declarative trivalued game-based semantics for DeLP that is sound and complete for DeLP operational semantics. Complexity theory has become an important tool for comparing different formalism and for helping to ...

This timely publication features thoroughly researched articles on the topics of artificial moral agency, cyber-warfare, transhumanism, organic neural nets, human worker replacement, automaticity and global governance, security and surveillance, military drones, and more.

Prolog's DCG package is suitable to create top-down parsers easily – not even determinacy is a demand, because Prolog can easily manage it. This, however, means some loss of efficiency in a number of cases, when grammatically significal words are appearing in the end of sentences, because we must backtrack deeply in such cases. To process free word order languages is likewise hard. The article talks about the operation of a DCG parser, but in a Contralog environment. This solves just the problem mentioned before: from the DCG grammar description it generates a bottom-up parser. Összefoglaló A Prolog ba épített DCG csomaggal könnyen lehet fentről lefelé haladó nyelvi elemzőket létrehozni, ahol még a determinisztikusság sem követelmény – a Prolog mindezt jól kezeli. Ám ugyanez hatékonyságvesztést is jelenthet egy sor olyan esetben, ahol a szignifikáns nyelvi elemek a mondatok végefelé vannak, mert ilyenkor mély visszalépésekre van szükség, de ez szabad szórendű nyelvek elemzésekor sem eléggé hatékony. A dolgozat a korábban már közölt Contralog nevű Prolog kiterjesztésre épülő DCG elemző működését tárgyalja, amely éppen az említ ett gondot oldja meg: a DCG nyelvtanleírásból egy alulról felfelé haladó elemző algoritmus működtetésével. Kulcsszavak Prolog, DCG, alulról felfelé haladó elemzés, természetes nyelvek elemzése 1. BEVEZETÉS A nyelvtani elemzés (parsing) témaköre egy igen lén yeges kérdés egy sor szoftver termékben. Nem csak a természetes nyelveket elemző vagy fordító, jobbára kísérleti szoftverekről van szó, hanem a legkülönfélébb gyakorlati területről is, ahol kisebb-nagyobb bonyolultságú, és általában valamilyen kézenfekvő célra használt formális nyelv mondatainak elemzése a feladat. A nyelvtani elemzés feladata az adott mondat és a mondatszimbólum, mint nemterminális közötti elemzési fának (környezetfüggetlen esetben), ill. elemzési gráfnak a megkeresése és előállítása. Az e lemzési fa gyökéreleme a mondatszimbólum (nemterminális), a levélelemei pedig a bemenő célnyelvi mondat egyes terminális szimbólumai. Ha elemzési fából csak egyetlenegy létezik bármilyen bemenő mondatra, akkor a nyelvtan egyértelmű, egyébként többértelmű. Az elemzés feladata nemdeterminisztikusan is érthető: többértelmű nyelvtan esetén az elemzésnek az összes lehetséges elemzési fát elő kell állítania [1]. Az elemzési fa előállítása során a fa mérete a bemenő mondat hosszával négyzetes arányban van, míg a p árhuzamos elemzések fái még egy további szorzót eredményeznek. Az elemzés helyigénye tehát általános esetben szintén a mondat hosszával kb. köbös N 3 arányban van. A köbös